It’s about time I did a bit of an update of where I’m at with my PhD. I’m over the 2.5 year mark, which is pretty terrifying actually, and I’m nearly finished my final season of data collection. It’s quite stressful knowing that so much is riding on the results and hoping that all the hard work pays off. But some things are just out of your control, and that is especially true when you’re working in the real world, outside the controlled conditions of a lab. I’ve had a few mishaps along the way that have caused stress and delays (luckily nothing disastrous!), but that’s all part of working with nature.

Over the fence

In a previous post I talked about part of my research looking at the impact of bettongs on a native lily, the early nancy (Wurmbea dioica), which have a bulb that is apparently irresistible to bettongs. I’ve been monitoring populations of early nancy in Mulligans Flat reserve for 3 years now, to look at whether the bettong predation is having a negative (or positive) effect over time. I started with five sites across the reserve, with plots inside and outside fenced areas that were supposed to exclude the bettongs to provide a control. In the first year of monitoring the fences were doing their job, but over the next few months I noticed some tell-tale diggings appearing inside the fenced areas. The bettongs had not only worked out how to get underneath the fences and squeeze through the gaps around the gates, but they could actually climb over! We were amazed that they were able to do this with their tiny t-rex front legs, but they were as agile as possums.

Early nancy monitoring plots, over three years from 2015-2017. Yellow markers are seedlings, red markers are adult plants, and blue markers indicate where a plant has been dug up or buried by a bettong. This area was fenced to exclude bettongs, but between the 2015 and 2016 sessions bettongs worked out how to get in – the results are pretty clear. 

It was pretty clear that the fences weren’t going to keep them out any more. By the time I did the second year of monitoring, there were bettong diggings everywhere and many of the early nancies had been eaten. I no longer had a control group for my study – so I found four more populations outside the sanctuary, where the bettongs definitely couldn’t get to them! The first year of data I collected isn’t useless though, and I’ve continued to monitor those sites to see the impact of the bettongs. It will make the analysis a little more difficult though!

I have also had problems with pegs and markers mysteriously disappearing. At one site this year I spent about half an hour trying to find one of my plot markers, then gave up and decided to come back the next day – only to find that another had gone missing overnight! I suspect cockatoos are the culprits, judging by the beak marks in the ground nearby.

It never rains but it pours

Flooding at Mulligans Flat

Last year I set up an experiment to measure the effects of bettong digging on seed germination. I added seeds from native grassland forbs into bettong diggings and then counted how many seedlings germinated. To give the seeds the best chance of germinating, I wanted to sow them in autumn, after we’d had some good rain. But the rain just didn’t come – we had an extremely dry autumn with barely any rainfall until mid May. I waited for weeks, worrying that the rain would never come. But when the drought finally broke, there was no stopping it. Last winter was one of the wettest on record, and we realised why the reserve was called Mulligans ‘Flat’. Many of my sites were under water for weeks, and the bettong diggings were like tiny little ponds. I went from being worried that nothing would germinate because it was too dry, to watching the water washing away my seeds and drowning anything that tried to grow. Sometimes the flooding was so bad that the tracks were washed away and parts of the reserve were inaccessible – which does make field work a little difficult!

Bettong digging full of water

By November when I went to count the seedlings that had grown, I was very nervous about what I would find. Luckily, not everything had been washed away and I did have good germination despite many of the sites being under water. However, the extremely wet conditions are likely to have had an effect on the results, particularly which species did well. This year the winter was very dry, and it will be interesting to see how this affects the results when I finish my field work in November.

Dealing with unpredictability

Ask any researcher, particularly those working with natural systems, and I can guarantee they will have stories like these (and much worse!). Nature is unpredictable, and sometimes there is nothing you can do to ensure your experiment goes the way you planned. All we can do is try to allow for the inevitable missing markers and flooded experiments, and adapt our methods where we can. On the other hand, this unpredictability is a vital part of the ecosystems we study, and it makes the results all the more exciting!

echidna and plot
An unexpected visitor